This application relates generally to measuring network performance. More particularly, the disclosure provided herein relates to detecting and measuring network route reconvergence using in-band data probes.
Network route reconvergence, a phrase used broadly to refer to various measures and/or aspects of amounts of network traffic that is re-routed from a primary or preferred path to a secondary path, can be measured in a number of ways. In some instances, network route reconvergence is measured using inferred network reconvergence due to network impairments such as loss, reordering, and the like. In other instances, data probes are inserted into various parts of a network to measure actual observed network reconvergence at those parts of the network.
Actual observed network reconvergence can be measured, for example, by examining the values stored in the time-to-live field (“TTL”) of the data probes. Unlike inferred network reconvergence, the TTL field accurately and unambiguously represents network reconvergence as the TTL field value is decremented at each network “hop” or node. Analysis of the TTL field of the data probes therefore can provide an accurate and valuable picture of network route changes.
The TTL field reacts to any route changes experienced in the network. To obviate this, long-haul connections and/or distributed data probe generation devices can be used such that testing of various aspects of a network can be accurately tested. Thus, long out-of-band connections often exist between measurement devices and network insertion and/or extraction points such that the TTL field of the data probes reflect values based only upon network route changes experienced in particular portions of the network.